Last year Americans paid $274 billion in Medicare taxes and premiums. At the same time, the program paid out $564 billion in benefits. That amounts to a shortfall of roughly $290 billion. Looking into the future, even the most optimistic estimate by the program’s trustees puts Medicare’s future unfunded liabilities at more than $38.6 trillion. More realistic projections suggest the shortfall could easily top $90 trillion.*.

That is an almost nonsensical way to look at it. A portion of Medicare is paid for by payroll taxes. But a portion (mostly Part D) is paid from the general fund by statute. There is a "shortfall" in the same sense that the military has shortfall of $700 billion.